The BSA B40 with telescopic front forks was a modern motorcycle in its day and was used for convoy control, messenger services and the carriage of any small stores, which could be fitted into the pannier bags. The carriage of messages was an important function at a time when radios were few, and less reliable than now. Shepherding road convoys, particularly on major exercises, with the British Army of the Rhine in Germany, was a vital function. Motorcycles ensured that units did not become muddled, as there was often a set time allocation for the use of roads by military traffic with no allowances for losing the way.
Developed from the unit 250cc C15, the B40 350cc single offered greater flexibility and power output without an increase in weight when compared to the smaller engine. The release of a large number of ex military B40's during the early eighties coincided with a growing interest in Pre 65 trials resulting in many of them being modified to trials motorcycles. The B40 continues to be a favorite in the pre 65 trials world and is well supported by specialist suppliers.